Convert from
Convert to
Select a unit in each column
⚗️ Scientific
nanoseconds microseconds
🌡️ Common
milliseconds seconds minutes hours days weeks months years

About time conversions

Time conversions are among the most frequently needed in everyday life — from converting minutes to hours for scheduling, to days and weeks for planning, to milliseconds for computing and performance measurement.

The SI base unit of time is the second. All other units are defined relative to it: one minute equals 60 seconds, one hour equals 3,600 seconds, and one day equals 86,400 seconds. Months and years use average values (30.44 days per month, 365.25 days per year) to account for calendar variation.

For the international definition, see the NIST reference on SI units of time.